Regular Expression not matching in notepad++

Question

I am trying to match this regular expression in notepad++, but I am getting an error saying that it is invalid.

My Regex:

{{#lsth:JointEntero_May_2015\|2015_May_([0-9]+)}}

What I am trying to match:

{{#lsth:JointEntero_May_2015|2015_May_8}}

Why is it failing?

Answer 1

The regex that works is

\{\{\#lsth\:JointEntero_May_2015\|2015_May_([0-9]+)\}\}

It is working because the { and } characters must be escaped in order to get matched as literal symbols. {} are usually used as quantifiers where we can set min and/or max characters corresponding to the preceding pattern to match. See the documentation :

Matches n copies of the element it applies to.

Matches n or more copies of the element it applies to.

Matches m to n copies of the element it applies to, as much it can.

Like the above, but match as few copies as they can. Compare with *? and friends.